The present invention pertains to the drying of moisture-laden granular materials, such as grain for example, and more particularly pertains to the drying and then the cooling of such materials by direct contact with heating and cooling gases. In one specific respect, the invention pertains to improvements in recirculating grain dryers wherein grain is dried by contact with hot air and is then cooled by contact with cooler air.
Grain dryers of the aforementioned type wherein wet grain is dried and then cooled by means of hot and cold air are well known and widely used. Some of the representative types are disclosed, for instance, in U.S. Pat. Nos. 1,669,012; 3,313,040 and 3,629,954, and it should be pointed out that such dryers are dependent upon circulation of relatively large volumes of hot and cold air if thorough drying and cooling of the grain at a satisfactory rate is to be obtained. As a consequence, the thermal and electrical energy requirements for drying of grain can be substantial. In addition, there can be objections to such dryers when excessive amounts of chaff, husks, dust, etc., are discharged into the atmosphere along with the gases that are exhausted therefrom. Further objections have been raised when the dryer emits objectional noise or requires a pressurized enclosure.
It is therefore an object of the present invention to provide for the drying of granular materials in a manner whereby the energy requirements for drying are reduced.
Another object is to provide a dryer having improved means for cooling granular material following the drying thereof.
Yet another object is to provide for the drying of granular material in a manner whereby emission of objectionable substances into the atmosphere is alleviated.
Still another object is to provide a dryer for granular material whereby the emission of noise at objectionable levels is alleviated.
Even another object is to provide an improved grain dryer.
Another object is to reduce the cost of drying grain.
Other objects and advantages of the invention will become apparent from the following description and the appended claims.